US8550180B2 - Bearing of a breaking device tool - Google Patents

Abstract

The invention relates to a method for fitting a breaking device tool with a bearing, a breaking device and a tool bushing. The tool of the breaking device is fitted with a bearing with at least one bearing bushing manufactured of bearing material and arranged in a bearing space. There is a clearance fit between the bearing bushing and the bearing space, whereby the bearing bushing is insertable into the bearing space by manual force. During the use, compression stress pulses are given to the tool with a percussion device, whereby stress waves travel in the tool, which waves generate on the tool surface a movement in the direction of its perpendicular. This movement is transmitted to the bearing bushing, and it deforms the bearing bushing in the radial direction in such a way that the bearing bushing is pressed against the bearing space.

Description

RELATED APPLICATION DATA

This application claims priority under 35 U.S.C. §119 and/or §365 to Finish Application No. 20065775, filed in Finland on Dec. 5, 2006, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The invention relates to a method for fitting a breaking device tool with a bearing, a breaking device and a tool bushing used for a bearing. The breaking device comprises at least a frame, a tool and a percussion device. By means of a percussion element in the percussion device, compression stress pulses are generated in the tool, which transmits them further to material to be broken. In a bearing space around the tool a bearing bushing is arranged, a sliding surface on the inner periphery of the bearing bushing fitting the tool with a bearing to be movable in the axial direction of the tool. The object of the invention is described in more detail in the preambles of the independent claims.

A breaking hammer is a breaking device used as a supplementary device of an excavator or another basic machine when the intention is to break for instance rock, concrete or other relatively hard material. The percussion device of the breaking hammer is used to give compression stress pulses to a tool attached to the breaking hammer, the tool transmitting the stress pulses to the material to be broken. At the same time, the tool is pressed against the material to be broken, whereby the effect of the stress waves and pressing causes the tool to penetrate into the material to be broken, which results in breaking of the material. The tool of the breaking device is mounted on a bearing in the frame of the breaking device in such a way that it can move in the axial direction during the breaking. The tool is usually mounted on a slide bearing by means of one or more bearing bushings. In known solutions, the bearing bushing is attached to a tool bushing that is, in turn, attached to the frame of the breaking device. The bearing bushing is a slide bearing that wears in use, due to which it has to be changed from time to time. A problem with known solutions is that it is difficult and slow to change a worn bearing bushing in working site conditions.

BRIEF DESCRIPTION OF THE INVENTION

An object of this invention is to provide a novel and an improved method for fitting a breaking device tool with a bearing, a breaking device and a tool bushing.

The method according to the invention is characterized by arranging a clearance fit between the outer diameter of the bearing bushing and the diameter of the bearing space; inserting the bearing bushing in the axial direction to its place in the bearing space without a force effect resulting from the reciprocal dimensioning of the diameters of the bearing bushing and the bearing space; and locking the bearing bushing during the use of the breaking device in the axial direction to be substantially immovable in such a way that the tool is subjected to compression stress pulses, whereby the stress waves in the tool generate a movement perpendicular to the surface of the tool, which movement is transmitted to the bearing bushing, causing plastic deformation to the bearing bushing, and the bearing bushing to be locked in place in the bearing space.

The breaking device according to the invention is characterized in that a clearance fit is arranged between the outer diameter of the bearing bushing and the diameter of the bearing space; that the bearing bushing is of deformable bearing material; that the bearing bushing is prevented in the axial direction from getting out of the bearing space after the mounting; and that the bearing bushing is locked in place in the bearing space during the use of the breaking device when the stress waves in the tool and the movement in the direction of the perpendicular of the tool surface due to the waves have caused the bearing bushing to be deformed against the bearing space.

The tool bushing according to the invention is characterized in that there is a clearance between the outer diameter of the bearing bushing and the bearing space, whereby the bearing bushing is movable in the axial direction against the shoulder and away from it without the bushing frame preventing it; that the tool bushing comprises at least one locking means with which the bearing bushing is prevented in the axial direction from getting out of the bushing frame; and that the bearing bushing is of deformable material, whereby it is arranged, during the use of the breaking device, to be deformed and to lock immovably in the bearing space.

An idea of the invention is that the breaking device tool is arranged through at least one bearing bushing, which fits the tool with a bearing in such a way that the tool can move in the axial direction relative to the frame of the breaking device. The bearing bushing is an elongated piece made of slide bearing material and arranged in the bearing space. A clearance fit is arranged between the outer diameter of the bearing bushing and the bearing space to facilitate the mounting of the bearing bushing. During the use, the bearing bushing is arranged to be subjected to stress waves of the compression stress pulses traveling in the tool, whereby the bearing bushing is arranged to be deformed by the effect of the stress waves. The periphery of the bearing bushing is enlarged in the direction of the periphery and deformed. The enlargement of the bearing bushing periphery results in compression stress between the bearing bushing and the bearing space, which locks the bushing to be immovable. Thus, in the solution according to the invention, the stress waves generated by a percussion device have two tasks: primarily they contribute to the breaking of the material to be treated, but they also cause the bearing bushing of the tool to be actually attached to its place in the bearing space.

An advantage of the invention is that the bearing bushing can be easily inserted in the axial direction to its place in the bearing space, since there is a clearance fit between the bearing space and the bearing bushing. No special pressing tools or the like are required for the mounting, but the bearing bushing can be inserted into the bearing space with manual force. Further, the bearing bushing is a simple utility item the manufacturing costs of which are small.

The idea of an embodiment of the invention is that the bearing bushing is prevented in the axial direction from getting out of the bearing space by means of one or more prelocking members. The prelocking member keeps the bearing bushing temporarily in place until the bearing bushing is deformed and actually attached to the bearing space.

The idea of an embodiment of the invention is that at least one bearing space is positioned at the lower end of the breaking device on the side of the tool in such a way that the bearing space is open downwards in the axial direction. Thus, the bearing bushing is insertable in the axial direction from below to its place in the bearing space without having to disassemble the lower frame of the breaking device. For changing, only the tool needs to be detached. An advantage of this embodiment is that it is quick and simple to change the bearing bushing. Further, since there is no need to disassemble structures of the breaking device, the changing may also take place in dirty working site conditions. As it is possible to change the bearing bushing in the working site, the interruption in the use of the breaking device can be as short as possible.

The idea of an embodiment of the invention is that the breaking device comprises a tool bushing comprising a bushing frame the inner circle of which forms a bearing space for the bearing bushing. The bushing frame may be immovably attached to the frame of the breaking device by means of one or more locking means. The bearing bushing is arranged to be deformed during the operation of the breaking device in such a way that it is pressed against the inner periphery of the bushing frame in the radial direction. The strength of the bushing frame is dimensioned to be greater than that of the bearing bushing so that substantially only the bearing bushing is deformed by the effect of stress waves. An advantage of this embodiment is that the bushing frame and the bearing space in it may be detached and changed, if required. Further, the tool bushings of the present breaking devices already in use may be replaced with tool bushings according to this embodiment, after which it will be easier to change the bearing bushings in the future.

The idea of an embodiment of the invention is that the bearing space is formed directly in the frame of the breaking device. Thus, the bearing bushing is arranged to be deformed against the frame of the breaking device during the use of the device. An advantage of this embodiment is that the breaking device does not need a separate bushing frame to form a bearing space. Thus, the diameter of the hole to be made around the tool in the breaking device frame may be smaller than when a separate detachable bushing frame is used, which reduces the manufacturing costs. In addition, there is no need to manufacture a bushing frame. Furthermore, the bearing space formed in the breaking device frame is particularly firm, whereby it can well receive the compression stress of the bearing bushing deformed during the use.

The idea of an embodiment of the invention is that the bearing bushing is of bearing bronze. Bearing bronze suits well to be used as the slide bearing of a breaking device tool, because it is deformed relatively easily due to the effect of stress waves, still having sufficient yield strength so that deformation causes compression stress in it, which keeps the bearing bushing in place in the bearing space due to the friction between the bearing bushing and the bearing space. Further, an advantage of bearing bronze is that it endures also short-term dry use without getting damaged when, for some reason or other, there is no lubricant film between the bearing bushing and the tool.

The idea of an embodiment of the invention is that the wall thickness of the bearing bushing is between 8 and 12 mm. Thus, the bearing bushing is sufficiently firm, so that sufficient compression stress is generated in it as a result of radial deformation. If the bearing bushing is not sufficiently firm, it does not stay properly in place in the bearing space. On the other hand, the wall thickness of the bearing bushing may not be so great that stress waves are not sufficient to generate deformation.

The idea of an embodiment of the invention is that the bearing bushing is prevented, by means of one or more prelocking member of light material, from getting out of the bearing space. An advantage of a lightweight prelocking member is that it is not subjected to such great acceleration forces during the operation of the percussion device as would a piece manufactured of denser material. The density of the prelocking member may be clearly smaller than that of the frame material. The density of the prelocking member material may be below 3 000 kg/m³, whereas the density of the frame that is typically steel is about 8 0000 kg/m³. Thus, the prelocking member may be manufactured of, for example, plastic material or reinforced plastic that has been reinforced with carbon, aramid or glass fibres or the like fibres. Further, the prelocking member may be manufactured of light metal, such as aluminum alloy. Furthermore, it may be manufactured of fibre material or even rubber. A prelocking member manufactured of light material does not, due to vibration, deform the locking surface made for it, such as a locking groove, locking opening or the like, because the acceleration forces directed at the prelocking member are relatively small. On the other hand, a prelocking member manufactured of less dense material is usually softer than a locking surface manufactured of denser material. A prelocking member manufactured of less dense material than the locking surface may wear during the use due to vibration, but this has no significance because the purpose of the prelocking member is to keep the bearing bushing in the bearing space only until some stress compression pulses have been given to the tool by the percussion device and until the stress waves in the tool have deformed the bearing bushing in such a way that it is firmly pressed into the bearing space.

The idea of an embodiment of the invention is that the prelocking member is a ring manufactured of plastic material, arranged in a groove on the periphery of the bearing space. It is simple and quick to arrange such a locking ring in place. Further, it is easy to manufacture inexpensive high-quality locking members of plastic material.

BRIEF DESCRIPTION OF THE FIGURES

Some embodiments of the invention will be described in more detail in the attached drawings, in which

FIG. 1 shows schematically a side view of a breaking hammer arranged in the boom of an excavator;

FIG. 2 shows schematically generation of a compression stress pulse in a tool that transmits the generated stress waves to the material to be broken;

FIG. 3 shows schematically a cut-open part of the lower part of a breaking device;

FIG. 4 shows schematically a side view of a cut-open tool bushing;

FIG. 5 shows schematically a side view of the cut-open bushing frame of the tool bushing according toFIG. 4;

FIG. 6 shows schematically a side view of the cut-open bearing bushing of the tool bushing according toFIG. 4;

FIG. 7 shows schematically an open-cut part of the lower part of another breaking hammer;

FIG. 8 shows schematically a cross-section of the bearing of a tool according to the invention, seen from the longitudinal direction of the tool, before the bearing bushing has been deformed;

FIG. 9 shows schematically a cross-section of the bearing of a tool according to the invention, seen from the longitudinal direction of the tool, after the bearing bushing has been deformed by the effect of stress waves;

FIG. 10 shows schematically a cross-section indicating alternative ways to remove the bearing bushing deformed into the bearing housing;

FIG. 11 shows schematically a side view of a rock drilling machine; and

FIG. 12 shows schematically an open-cut structure of a rock drilling machine.

For the sake of clarity, embodiments of the invention are shown simplified in the figures. Similar parts are indicated with the same reference numerals.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

InFIG. 1, a breaking hammer1 is arranged on aboom3 in anexcavator2. The breaking hammer1 may be a hydraulic, pneumatic or electric device. The breaking device1 is pressed by means of theboom3 againstmaterial4 to be broken at the same time as compression stress pulses may be given to atool6 connected to the hammer with apercussion device5 in the hammer, and thetool6 transmits the stress pulses to the material to be broken. Thepercussion device5 usually comprises a reciprocating percussion piston striking a percussion surface at the upper end of thetool6. In some cases, the percussion element may be an element other than a reciprocating percussion piston. Further, there may be a protective casing around the breaking hammer1, protecting it against damages and impurities.

It can be noted that in this application thelower part1aof the breaking hammer refers to the end on the side of thetool6, while theupper part1bof the breaking hammer refers to the end by which the breaking hammer1 is attachable to theboom3 or the like. Further, the breaking hammer1 may be arranged in any movable basic machine or, for instance, on a boom attached to a fixed base, such as a rock crusher.

FIG. 2 shows a very simplified operating principle of a breaking device. Apercussion element7 of thepercussion device5 generates in thetool6 compression stress (−), which propagates in thetool6 as stress waves. When a stress wave has reached the outermost end of thetool6, part of it may move on to thematerial4 to be broken, and part may return as a reflected wave back towards thepercussion device5. Traveling in thetool6, thestress wave6 generates a suddensmall bulge8 in thetool6, in other words there is a sharp hammering movement9 in the direction of the perpendicular of the tool surface in thetool6.

Further, it can be seen fromFIG. 2 that thetool6 is bearing-mounted on aframe10 in the breaking device1 by means of one ormore bearings11. Thebearing11 is a slide bearing that is in contact with thetool6. Thus, the radial hammering movement in thetool6 is transmitted from the surface of thetool6 also to thebearing11, this feature being utilized in the actual attaching process of the bearing11 in the invention.FIGS. 3 to 10 and the related description present embodiments and details of the bearing in greater detail.

FIG. 3 shows a part of thelower part1aof the breaking hammer. Thepercussion element7 may be a movable percussion piston that strikes apercussion surface12 at the upper end of thetool6. Thetool6 is arranged in the axial direction in thepercussion element7 and may be supported against theframe10 by means of anupper bearing bushing13 and alower bearing bushing14. The breaking hammer1 may comprise retainer means allowing a predetermined axial movement for thetool6 but preventing thetool6 from getting completely out of the breaking device1. Such retainer means may comprise one or more cross-direction retainer pins15, for which a cross-direction opening is formed in theframe10. Further, in order for thetool6 to be able to move relative to theretainer pin15, a thinnedportion16 may be formed in it at the point of theretainer pin15. Theupper bearing bushing13 may be arranged in theupper bearing space17 from the direction of thepercussion element7 when the frame of the breaking device has been disassembled. Theupper bearing bushing13 may be supported in the axial direction with ashoulder18 and a counter-ring19 or the like. Theupper bearing bushing13 may be manufactured of slide bearing metal, and it may contain lubricant channels along which lubricant may be conveyed to its slide surfaces.

The lower part of theframe10 is provided with aspace20 open towards the outer surface of theframe10, in which space20 atool bushing21 is arranged from below, in the mounting direction A, thetool bushing21 comprising abushing frame22 and alower bearing bushing14 arranged inside it. Thetool bushing21 is supported by its upper end against ashoulder23 in theframe10 and locked with one or more locking means, such as across-direction locking pin24aand lockinggrooves24band24cin such a way that it cannot get out of thespace20. The inner periphery of thebushing frame22 forms a bearingspace25, into which the bearingbushing14 is inserted. The end of thebushing frame22 on the side of the percussion element may comprise ashoulder26, against which the bearingbushing14 may be inserted. Alternatively, the movement of the bearingbushing14 in the axial direction may be prevented in such a way that theshoulder23 in theframe10 extends to the portion of the bearingbushing14 as well. In the portion of the opposite end of thebushing frame22, there may be agroove27, which may be provided with aprelocking member28, such as a ring made of plastic material. The purpose of the prelockingmember28 is to prevent the bearingbushing14 from getting out of the bearingspace25 after the mounting and before the bearingbushing14 has been attached to the bearingspace25 as a result of the deformation. Alternatively, the prelockingmember28 may be a cross-direction pin or another member suitable for the purpose. When thelower bearing bushing14 has worn out, it may be replaced through the lower part of the breaking hammer without having to disassemble the lower part of theframe10, or without even having to detach thetool bushing21.

It can be seen fromFIG. 3 that the bearingbushing14 may be provided with one ormore lubricant channels29, along which lubricant may be conveyed to its slide surfaces. Correspondingly, thebushing frame22 may comprisechannels30, as may theframe10, for conveying lubricant to the bearingbushing14.

FIG. 4 shows the assembledtool bushing21.FIG. 5 shows thebushing frame22 and the diameter D1 of the bearingspace25.FIG. 6, in turn, shows the bearingbushing14 and its outer diameter D2. In order to insert the bearingbushing14 into the bearingspace25 without difficulty in the mounting direction A, the diameter D1 has been dimensioned greater than the diameter D2, in other words there is a small clearance between the bearingbushing14 and the bearingspace25. The components arranged within each other have thus a clearance fit. Further, the distance between theshoulder26 and thegroove27 in thebushing frame22, i.e. the length L1 of the bearingspace25, is greater than or equal to the length L2 of the bearingbushing14 in order for the bearingbushing14 to be arrangeable inside thebushing frame22.FIG. 6 further shows theouter periphery31 of the bearingbushing14, serving as the attachment surface against the bearingspace25, and theinner periphery32 of the bearingbushing14, serving as the slide surface against thetool6. Further,FIG. 6 indicates the wall thickness W of the bearingbushing14, which may be between 8 to 12 mm. Thus, the bearingbushing14 is sufficiently firm so that required compression stress can be generated in it as a result of radial deformation. If the bearingbushing14 is not sufficiently firm, it does not stay properly in place in the bearingspace25. On the other hand, the wall thickness W of the bearingbushing14 may not be so great that the stress waves9 are not capable to generate radial deformation in the bearing bushing. Furthermore,FIG. 6 indicates the inner diameter D3 of the bearingbushing14, dimensioned greater than the outer diameter of thetool6 in order for the slide bearing to function in general.

FIG. 7 shows an alternative structure of thelower part1aof the breaking hammer, in which, deviating fromFIG. 3, there is nobushing frame22 but thelower bearing bushing14 is arranged in the bearingspace25 formed in the lower part of theframe10. The lower part of the bearingspace25 may extend as far as to the outer surface of the lower part of theframe10, whereby the bearingbushing14 may be pushed in the mounting direction A from below to its place in the bearingspace25 without having to disassemble theframe10. The bearingbushing14 may be supported by its upper end against theshoulder23 formed in theframe10. By its lower end, the bearingbushing14 may be supported with asuitable prelocking member28 at least until it has been deformed in the radial direction against the bearingspace25 and locked in place.

FIGS. 8 and 9 illustrate how the bearingbushing14 is attached to the bearingspace25. The stress waves9 traveling in thetool6 generate on the tool surface a movement in the direction of its perpendicular, the movement being transmitted to the bearingbushing14. This small hammering movement is illustrated with arrows inFIG. 8. After the mounting, there is asmall clearance33 between the bearingbushing14 and the bearingspace25. The hammering movement due to the stress waves shapes the bearingbushing14 and causes the bearingbushing14 to expand, whereby its outer periphery is pressed against the bearingspace25, and theclearance33 disappears.

It is seen fromFIG. 9 that during the use thetool6 is supported, due toclearances39 between thetool6 and the bearingbushing14, against onesupport point36 of the side of the bearingbushing14. In practice, thetool6 becomes thus positioned eccentrically inside the bearingbushing14. Due to this, during one stress wave, hammering movement is transmitted to the bearingbushing14 essentially only at thesupport point36. As seen fromFIG. 9, for example the opposite side of thesupport point36 has amaximum clearance39a, and the small bulge on the surface of thetool6 is not capable of affecting the bearingbushing14. However, the position of thetool6 inside the bearingbushing14 changes continuously during the use of the breaking hammer, so that forces which deform are directed at different points on the periphery of the bearingbushing14. When thesupport point36 is subjected to aradial force37 caused by a stress wave and shown inFIG. 9, the bearingbushing14 is pressed between thetool6 and the bearinghousing25, due to which the periphery of the bearingbushing14 tends to stretch in the way indicated witharrows38. When the periphery of the bearingbushing14 stretches, it expands and causes radial deformation of the whole bushing. The diameter of the bearingbushing14 enlarges permanently, and the bushing is firmly pressed against the bearinghousing25.

The bearingspace25 may be of steel or corresponding material that is stronger than the bearing material and is capable of receiving the compression stress caused by the expansion of the bearingbushing14 without the bearingspace25 being essentially deformed. The bearingbushing14 may be manufactured of suitable bearing metal, such as bearing bronze. Alternatively, the bearingbushing14 may be manufactured of any deformable slide bearing material, even plastic material or the like.

FIG. 10 illustrates two alternative ways to remove the bearingbushing14 deformed by the stress waves9 from the bearingspace25. Before removing the bearingbushing14, thetool6 is detached, and theprelocking member28 is removed if it is still there after the use. Subsequently, one or morelongitudinal welding beads34 may be welded on the inner periphery of the bearingbushing14, which causes the bearingbushing14 to contract in such a way that it can be drawn out of the bearingspace25. One possibility is to cut in the bearing bushing14 a longitudinal through-groove35, in which case the bearingbushing14 may be pressed into a smaller diameter and subsequently drawn out of the bearingspace25. The bearingbushing14 can be removed with conventional tools in working site conditions.

It is also feasible to apply the solution according to the invention in connection with the upper bearing bushing13 of the breakinghammer tool6. In such a case, also theupper bearing bushing13 is attached to its place in theupper bearing space17 by using stress waves9 traveling in thetool6, which stress waves deform the bearingbushing13 in the radial direction and cause it to be pressed firmly against the bearingspace17. Theupper bearing bushing13 may be supported against the bearingspace17 with one ormore prelocking members28, due to which it is not necessary to support it in the way shown inFIG. 3 by means of ashoulder18 and a counter-ring19.

FIG. 11 shows arock drilling machine40, which may be arranged on afeed beam41 on theboom3 of the rock drilling rig. Therock drilling machine40 is also some kind of a breaking device comprising apercussion device5. By means of thepercussion element7 in thepercussion device5, a compression stress pulse may be generated in thetool6 on an extension of thepercussion device5. Thetool6 may comprise adrill shank6aand one ormore extension rods6band6c, and further, there may be adrill bit6dat the outermost end of the tool. Therock drilling machine40 may further comprise arotating device42, with which thetool6 can be rotated around its longitudinal axis. Furthermore, therock drilling machine40 may be moved by means of afeed device43, supported by thefeed beam41. In this application, the end of therock drilling machine40 on the side of thedrill shank6amay be called the lower part or the lower end.

FIG. 12 shows the structure of therock drilling machine40. Thedrill shank6amay be supported against theframe10 with one ormore bearing bushings14 manufactured of slide bearing material. The bearingbushing14 is arranged in the bearingspace25 that may be formed directly in theframe10 of the rock drilling machine or in a separate piece attachable to and detachable from a space formed in the frame for this purpose. The bearingspace25 may be arranged at the lower end of therock drilling machine40, i.e. at the end on the side of thedrill bit6a, in such a way that the bearingbushing14 may be inserted to its place without disassembling theframe10. The preattachment of the bearingbushing14 and the actual locking in place in the bearingspace25 may take place in the ways described earlier in this application. After the bearingbushing14 has been mounted, the rotation is switched off until the impact pulses given with the percussion device have caused the bearingbushing14 to be deformed and pressed into the bearingspace25. After this, the rotation may be switched on, and the normal drilling may be started.

In some cases, the features presented in this application may be used as such, irrespective of the other features. On the other hand, features described in this application may, if required, be combined to form different combinations.

The drawings and the related description are only intended to illustrate the idea of the invention. Details of the invention may vary within the scope of the claims.

Claims (22)

What is claimed is:

1. A breaking device comprising:

a frame,

a percussion device having a percussion element for generating compression stress pulses,

a tool arranged on the extension of the percussion element and arranged to transmit the compression stress pulses to material to be broken as stress waves, and

at least one bearing bushing arranged in a bearing space around the tool, which bearing bushing is of bearing material, whereby it is arranged to form a slide bearing for the tool moved in the axial direction,

wherein an initial clearance space in the radial direction is arranged between the outermost diameter of the bearing bushing and the diameter of the bearing space,

wherein the bearing bushing is of permanently deformable bearing material such that when deformed the material is permanently deformed,

wherein the bearing bushing is prevented in the axial direction from getting out of the bearing space after the mounting, and

wherein the bearing bushing is locked in place in the bearing space in both the axial and radial directions during the use of the breaking device when the stress waves in the tool and the movement in the direction of the perpendicular of the tool surface due to the waves have caused the bearing bushing to be enlarged in the direction of the periphery and radially deformed against the bearing space to lock the bushing immovably axially and radially in the bearing space.

2. A breaking device according toclaim 1, wherein the bearing bushing is prevented in the axial direction from getting out of the bearing space after the mounting by means of at least one prelocking member.

3. A breaking device according toclaim 1, wherein

the bearing bushing is prevented in the axial direction from getting out of the bearing space after the mounting by means of at least one prelocking member, and

the prelocking member is manufactured of light material, the density of which is below 3000 kg/m³.

4. A breaking device according toclaim 1, wherein

the breaking device comprises a tool bushing that is a separate piece attachable to the frame of the breaking device,

the tool bushing comprises an elongated bushing frame having an outer periphery and an inner periphery, and

the inner periphery of the bushing frame serves as the bearing space, in which the bearing bushing is arranged.

5. A breaking device according toclaim 1, wherein the bearing space is formed directly in the frame of the breaking device.

6. A breaking device according toclaim 1, wherein the bearing bushing is manufactured of bearing bronze.

7. A breaking device according toclaim 1, wherein the breaking device is a breaking hammer.

8. A breaking device according toclaim 1, wherein the breaking device is a rock drilling machine.

9. A breaking device according toclaim 1, wherein a wall thickness of the bearing bushing is 8 to 12 mm.

10. A breaking device according toclaim 1, wherein a periphery of the bearing bushing is non-slotted, or alternatively, the bearing bushing is solid.

11. A breaking device according toclaim 1, wherein the bearing bushing is solid.

12. A breaking device according toclaim 1, wherein the permanently deformed bearing bushing of the tool is attached to its place in the bearing space.

13. A breaking device comprising:

a frame,

a percussion device having a percussion element for generating compression stress pulses,

a tool arranged on the extension of the percussion element and arranged to transmit the compression stress pulses to material to be broken as stress waves, and

at least one bearing bushing arranged in a bearing space around the tool, which bearing bushing is of bearing material, whereby it is arranged to form a slide bearing for the tool moved in the axial direction,

wherein a clearance space in the radial direction is arranged between the outermost diameter of the bearing bushing and the diameter of the bearing space,

wherein the bearing bushing is of deformable metallic bearing material,

wherein the bearing bushing is prevented in the axial direction from getting out of the bearing space after the mounting, and

wherein the bearing bushing is locked in place in the bearing space in both the axial and radial directions during the use of the breaking device when the stress waves in the tool and the movement in the direction of the perpendicular of the tool surface due to the waves have caused the bearing bushing to be enlarged in the direction of the periphery and radially deformed against the bearing space to lock the bushing immovably axially and radially in the bearing space.

14. A breaking device according toclaim 13, wherein a wall thickness of the bearing bushing is 8 to 12 mm.

15. A breaking device according toclaim 13, wherein a periphery of the bearing bushing is non-slotted, or alternatively, the bearing bushing is solid.

16. A breaking device according toclaim 13, wherein the bearing bushing is solid.

17. A breaking device comprising:

a frame,

a percussion device having a percussion element for generating compression stress pulses,

a tool arranged on the extension of the percussion element and arranged to transmit the compression stress pulses to material to be broken as stress waves, and

at least one bearing bushing arranged in a bearing space around the tool, which bearing bushing is of bearing material, whereby it is arranged to form a slide bearing for the tool moved in the axial direction,

wherein an initial clearance space in the radial direction is arranged between the outermost diameter of the bearing bushing and the diameter of the bearing space,

wherein the bearing bushing is of deformable rigid bearing material,

wherein the bearing bushing is prevented in the axial direction from getting out of the bearing space after the mounting, and

wherein the bearing bushing is locked in place in the bearing space in both the axial and radial directions during the use of the breaking device when the stress waves in the tool and the movement in the direction of the perpendicular of the tool surface due to the waves have caused the bearing bushing to be enlarged in the direction of the periphery and radially deformed against the bearing space to lock the bushing immovably axially and radially in the bearing space.

18. A breaking device according toclaim 17, wherein a wall thickness of the bearing bushing is 8 to 12 mm.

19. A breaking device according toclaim 17, wherein a periphery of the bearing bushing is non-slotted, or alternatively, the bearing bushing is solid.

20. A breaking device according toclaim 17, wherein the bearing bushing is solid.

21. A breaking device comprising:

a frame,

a percussion device having a percussion element for generating compression stress pulses,

a tool arranged on the extension of the percussion element and arranged to transmit the compression stress pulses to material to be broken as stress waves, and

at least one bearing bushing arranged in a bearing space around the tool, which bearing bushing is of bearing material, whereby it is arranged to form a slide bearing for the tool moved in the axial direction,

wherein an initial clearance space in the radial direction is arranged between the outermost diameter of the bearing bushing and the diameter of the bearing space,

wherein the bearing bushing is prevented in the axial direction from getting out of the bearing space after the mounting,

wherein the bearing bushing is of permanently deformable bearing material, and

wherein the bearing bushing has been enlarged in the direction of the periphery and radially deformed, by the stress waves in the tool and the movement in the direction of the perpendicular of the tool surface due to the waves, to press against the bearing space to lock the bushing immovably axially and radially in the bearing space.

22. A breaking device according toclaim 21, wherein the initial clearance space disappears by the enlarged bearing bushing pressed against the bearing space.

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